A federal judge on Friday granted class certification to tens of millions of smokers in a lawsuit against cigarette makers, creating what may be the largest class action ever certified in U.S. legal history.

A national consortium of plaintiff lawyers won the key ruling when U.S. District Judge Okla Jones II in New Orleans cleared them to proceed on behalf of smokers in the United States and its territories who allegedly became addicted to nicotine.

The long-awaited ruling did not endorse the suit's central contention: that cigarette makers have long known their products are addictive but have concealed that information and manipulated nicotine levels to keep smokers hooked.

But by granting class certification to a vast number of current and former smokers--even those who have not been diagnosed with smoking-related ailments--the ruling raises the prospect of monumental damages should the plaintiffs ultimately prevail.

The decision makes the lawsuit "the largest class action ever certified in the history of the law," said Don Howarth of the Los Angeles law firm of Howarth & Smith, one of the plaintiff firms allied in the case.

"We're delighted," Howarth said. "This is absolutely 95% of what we wanted. It gives us the right to take on, in one action, the tobacco industry."

Industry officials voiced disappointment with the ruling and said they will appeal.

The two-year-old lawsuit is known as the Castano case, after Dianne A. Castano, one of four named plaintiffs and the widow of Peter Castano, a New Orleans lawyer who died of lung cancer that allegedly was caused by smoking.

Defendants include the Tobacco Institute and the seven biggest U.S. tobacco companies, who maintain that smoking is not addictive and those who want to quit can do so.

Industry lawyers had adamantly opposed class certification, contending, among other things, that the sheer number of potential claimants would make the case unmanageable.

"The court's decision to allow Castano to go forward as a class action, in our opinion, is inconsistent with class certification guidelines," R.J. Reynolds Tobacco said in a statement.

"If this case proceeds and is not reversed on appeal, it will prove to be an unwieldy burden on the court system."

Philip Morris Cos. said it also will appeal, but noted that Jones resolved some issues in the industry's favor--including rejecting an industry-paid fund to monitor smokers' health and fund their medical care.

And Philip Morris said that even if the industry is found liable, smokers will still have to prove damages on an individual basis.

Since the 1950s, cigarette makers have repulsed scores of lawsuits, preserving their record of never paying a nickel in settlements or judgments to those claiming injuries from smoking.

Juries generally have agreed that smokers accepted the risk, and armies of defense lawyers have vastly outmanned and outspent their opponents.

To overcome these obstacles, plaintiff attorneys have seized on the addiction argument and sought to even the odds through class-action claims.

A Florida law firm currently has two class actions pending in Florida state court: one claiming injuries to flight attendants from second-hand smoke, and the other on behalf of injured smokers generally.

However, the New Orleans case involves a powerhouse alliance of about 60 law firms, each committed to spending $100,000.

In his 34-page ruling, Jones said the class of "nicotine-dependent" smokers will include all smokers medically diagnosed as nicotine-dependent, as well as smokers who have been warned by their doctors that smoking is dangerous but who have not quit.

Invoking the Robert Frost poem, "The Road Not Taken," Jones acknowledged he was embarking "on a road certainly less traveled, if ever taken at all."

"This will be a daunting task with long, difficult days ahead," the judge said. "However, the court believes the resolution of these issues now will alleviate the constant need for duplicative resolution of these issues later in hundreds of courtrooms around the nation, a task unparalleled in scope."